about fetching datas from two tables

[devaobeth]

please help i have two table 1st name "main category" and another one is "sub category" in main category i have parent_id,parent_name,parent_desc and in sub category i have sid,parent_id, sname, sdesc the parent_id is main category data but i want to display the main category parent_name as heading and sub category related to parent_name will display under the parent_name pls helpme